Define is_name_token (and friends) to resolve some type: ignores (GH-2714)

Gets rid of a few # type: ignores by using TypeGuard.

src/black/__init__.py

@@ -37,6 +37,7 @@
 from black.const import DEFAULT_LINE_LENGTH, DEFAULT_INCLUDES, DEFAULT_EXCLUDES
 from black.const import STDIN_PLACEHOLDER
 from black.nodes import STARS, syms, is_simple_decorator_expression
+from black.nodes import is_string_token
 from black.lines import Line, EmptyLineTracker
 from black.linegen import transform_line, LineGenerator, LN
 from black.comments import normalize_fmt_off
@@ -1156,8 +1157,8 @@ def get_features_used(  # noqa: C901
         }
 
     for n in node.pre_order():
-        if n.type == token.STRING:
-            value_head = n.value[:2]  # type: ignore
+        if is_string_token(n):
+            value_head = n.value[:2]
             if value_head in {'f"', 'F"', "f'", "F'", "rf", "fr", "RF", "FR"}:
                 features.add(Feature.F_STRINGS)
 

src/black/linegen.py

@@ -9,6 +9,7 @@
 from black.nodes import ASSIGNMENTS, OPENING_BRACKETS, CLOSING_BRACKETS
 from black.nodes import Visitor, syms, first_child_is_arith, ensure_visible
 from black.nodes import is_docstring, is_empty_tuple, is_one_tuple, is_one_tuple_between
+from black.nodes import is_name_token, is_lpar_token, is_rpar_token
 from black.nodes import is_walrus_assignment, is_yield, is_vararg, is_multiline_string
 from black.nodes import is_stub_suite, is_stub_body, is_atom_with_invisible_parens
 from black.nodes import wrap_in_parentheses
@@ -137,7 +138,7 @@ def visit_stmt(
         """
         normalize_invisible_parens(node, parens_after=parens)
         for child in node.children:
-            if child.type == token.NAME and child.value in keywords:  # type: ignore
+            if is_name_token(child) and child.value in keywords:
                 yield from self.line()
 
             yield from self.visit(child)
@@ -813,9 +814,9 @@ def normalize_invisible_parens(node: Node, parens_after: Set[str]) -> None:
             elif node.type == syms.import_from:
                 # "import from" nodes store parentheses directly as part of
                 # the statement
-                if child.type == token.LPAR:
+                if is_lpar_token(child):
                     # make parentheses invisible
-                    child.value = ""  # type: ignore
+                    child.value = ""
                     node.children[-1].value = ""  # type: ignore
                 elif child.type != token.STAR:
                     # insert invisible parentheses
@@ -861,11 +862,11 @@ def maybe_make_parens_invisible_in_atom(node: LN, parent: LN) -> bool:
 
     first = node.children[0]
     last = node.children[-1]
-    if first.type == token.LPAR and last.type == token.RPAR:
+    if is_lpar_token(first) and is_rpar_token(last):
         middle = node.children[1]
         # make parentheses invisible
-        first.value = ""  # type: ignore
-        last.value = ""  # type: ignore
+        first.value = ""
+        last.value = ""
         maybe_make_parens_invisible_in_atom(middle, parent=parent)
 
         if is_atom_with_invisible_parens(middle):

src/black/nodes.py

@@ -19,11 +19,15 @@
     from typing import Final
 else:
     from typing_extensions import Final
+if sys.version_info >= (3, 10):
+    from typing import TypeGuard
+else:
+    from typing_extensions import TypeGuard
 
 from mypy_extensions import mypyc_attr
 
 # lib2to3 fork
-from blib2to3.pytree import Node, Leaf, type_repr
+from blib2to3.pytree import Node, Leaf, type_repr, NL
 from blib2to3 import pygram
 from blib2to3.pgen2 import token
 
@@ -260,8 +264,8 @@ def whitespace(leaf: Leaf, *, complex_subscript: bool) -> str:  # noqa: C901
             and prevp.parent
             and prevp.parent.type == syms.shift_expr
             and prevp.prev_sibling
-            and prevp.prev_sibling.type == token.NAME
-            and prevp.prev_sibling.value == "print"  # type: ignore
+            and is_name_token(prevp.prev_sibling)
+            and prevp.prev_sibling.value == "print"
         ):
             # Python 2 print chevron
             return NO
@@ -687,7 +691,7 @@ def is_yield(node: LN) -> bool:
     if node.type == syms.yield_expr:
         return True
 
-    if node.type == token.NAME and node.value == "yield":  # type: ignore
+    if is_name_token(node) and node.value == "yield":
         return True
 
     if node.type != syms.atom:
@@ -854,3 +858,19 @@ def ensure_visible(leaf: Leaf) -> None:
         leaf.value = "("
     elif leaf.type == token.RPAR:
         leaf.value = ")"
+
+
+def is_name_token(nl: NL) -> TypeGuard[Leaf]:
+    return nl.type == token.NAME
+
+
+def is_lpar_token(nl: NL) -> TypeGuard[Leaf]:
+    return nl.type == token.LPAR
+
+
+def is_rpar_token(nl: NL) -> TypeGuard[Leaf]:
+    return nl.type == token.RPAR
+
+
+def is_string_token(nl: NL) -> TypeGuard[Leaf]:
+    return nl.type == token.STRING